Present voice message systems use encoded voice samples to store both the system-generated announcement messages and the subscriber-recorded messages. Since about 2,000 bytes of memory are required to store each second of speech, the size of the system memory required to store the system announcements and the subscriber-recorded messages increases quickly with system size.
When two or more voice message systems are interconnected or networked together, communications typically take the form of a header and a voice message. The header typically includes subscriber identification (e.g., calling party's or message sender's name), message delivery time, and message status. Because of the large amount of data required to store a message sender's name as encoded voice samples, sender identification has only been available in text form or as a telephone number in the header. Consequently, display telephones have been required to provide a message recipient with the sender's identification in the form of text or a telephone number. Even if the header size could be increased, the transmission of the sender's name in encoded voice form would take about two to four seconds per name and add significantly to the overall telephone calling cost, and would have a substantial effect on the throughput of the message service system.
While the use of speech coding techniques has been applied to the encoded voice samples to reduce the size of memory needed by a voice message system, speech coding has not solved the above-identified problems.